1. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida1 1  A Primer on Capacity Principles  New Technologies  Public Sector Needs 22 September 20101 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida

2. 22  Signal and train control functions  Train control and dispatching  Signal systems and equipment  Capacity effects Part 2: Conventional Signaling and Train Control Technologies- A Primer 22 September 2010

3. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida3  Ensure Safety  Collision Prevention  Over speed prevention (some systems)  Train operations management  Set or authorize routes  Manage train priorities Advanced train control systems supplement and enhance, but do not replace these functions 22 September 2010

4. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida4 4  Central office  Dispatchers desks (work stations)  Remote switching (where available)  Track layout displays  Support software  Office to field communications (voice radio, “code line”)  Field installations  Wayside signals  Switches – powered and manual  Block systems  Track circuits  Interlockings – prevent conflicting signal and switch settings  Track-train communications (where applied) 22 September 2010

5. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida5  Track capacity depends on the technical features of office and field systems, especially:  Block system types (manual, automatic, CTC)  Block lengths  Use of track circuits for train detection  Switch control – powered or manual  Train speeds – freight and passenger 22 September 2010

6. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida6 6 Manual Block System (MBS) Station A Station B Dark Territory Authority Limit  Manual Generation of Authorities  Voice Transmission & Repeat (3-5 mins)  Voice Location Reporting & Authority Release  Manual Operation of Switches by Crew  Low Capacity Operation – e.g. branch lines 22 September 2010

7. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida7 7 Station A Station B Automatic Block Signals  Similar to MBS, except  Automatic Signals Protect Rear of Train  Roll up of Authority  Automatic detection of train using track circuits  Higher Capacity Operation – applied to lower traffic main lines 22 September 2010 MBS With Automatic Block System (ABS MBS With Automatic Block System (ABS )

8. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida8 8  Consists of Signals & Switches operated by central dispatcher  Major advantage is avoiding manual switch delays Supervisory Office Control and/or Indication Remote Control of Switches / Signals Centralized Traffic Control 22 September 2010

9. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida9 9  Authority conveyed by Signal Indication  Track Circuits convey train location to dispatcher  Block system protects train in block  Much higher capacity  Better train performance  Applied to most higher capacity main lines on US freight network outside terminal areas Centralized Traffic Control (cont) 22 September 2010

10. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida10 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida10 Speed Loaded Freight Passenger Or Commuter Higher Speed Passenger Block Design Distance Braking Curves – Mixed Freight and Passenger Traffic 22 September 2010   Block length is a function of freight train braking   Typically 2 – 3 miles length

11. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida11 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida11 Block A5 Signal A4 Train 2 Block A3 Direction of Travel Signal A1 Block A1 Train 1 Signal A3Signal A2 Block A4 Block A2 Block is occupied by train Normal Speed Zero Speed Caution Speed Normal Speed No Code G Y RG Block length fixed by maximum speed, civil limits, grade, and worst train braking distance. Wayside Signal Spacing 22 September 2010

12. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida12 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida12 Additional aspects provide finer control of train movement, at additional cost and complexity. Trains operating at different speed limits may require different rules. Block A6 Signal A5 Train 2 Block A3 Signal A1 Block A1 Train 1 Signal A3 Signal A2 Block A5 Block A2 Normal Speed Zero Speed G/R Signal A4 Y/G Block A4 G/R R/R Y/R Caution Speed Normal Speed No Code Advanced Approach Block is occupied by train Signal Spacing - Options 22 September 2010

13. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida13  Most conventional systems rely on engineer compliance with signals and operating rules  Automated systems provide in cab displays and may enforce compliance  Principal systems are:  Automatic Train Stop – ATS  Enforce braking if engineer fails to respond to signals  Normally 8 second delay before enforcement  Automatic Cab Signals - ACS  Automatic Train Control – ATC  Civil Speed Enforcement – NEC and some NJT only 22 September 2010

14. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida14 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida14  Aspect transmitted display in engineer’s cab  Brakes apply automatically if authority is exceeded  Used on NEC, LIRR, MNCR, NJT, limited elsewhere Direction of Travel Train Signal Data Code Generator Code Transmission in Rails Code Pick-Up Coils Speedo Brake Interface Processor Signal Data Driver’s Panel Two types: Intermittent Continuous Cab Signals 22 September 201022 September 2010 22 September 2010

15. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida15 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida15 No changes can occur while train is outside of limited intervals. Speed authorization is passed to train at limited intervals, typically at signal locations. Train stores information until next authorization is received. Intermittent, ATS, ACS, ATC 22 September 2010

16. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida16 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida16 Speed authorization is continuously updated to vehicle. Changes in speed authority can be made at any time, and are visible to operator immediately. Capability to increase traffic; immediate recognition of aspect upgrades allow quicker response. Loss of signal is most restrictive, stopping train. Train requires no ‘memory.’ 22 September 2010 Continuous ATS, ACS, ATC

17. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida17 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida17 Signal A2 Signal A4 Signal A1 Train 2Train 1 G Y RG Signal A3 Without ATP, Train 2 continues to slow throughout block, even though Train 1 proceeds past Signal A1. Y Signal A2 Signal A4 Signal A1 G Y RG Signal A3 With ATP, Train 2 can resume normal speed as soon as Train 1 proceeds completely past Signal A1, increasing capacity Y G Train 2 Train 1 Advantages of Continuous Automatic Systems 22 September 2010

18. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida18 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida18 Home Signal - Controls entrance into interlockings. Most restrictive display is “STOP.” Distant Signal - Last automatic signal before a home signal. Most restrictive display is usually “Stop and proceed.” Intermediate Signals - Non-controlled signals other than distant signals – Aspect display cascades from next signal aspect. Most restrictive display is “Stop and Proceed.” Types of Signals 22 September 2010

19. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida19 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida19 Signals indicate authorized speed:  Speed Signaling  Displays speed at this and next signal  Turnouts speeds displayed where applicable  Requires many signal aspects  Applied on the NEC Types of Signal – Speed Signaling 22 September 2010

20. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida20 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida20  Route Signaling  Displays 3 or 4 Aspects  Clear, (double Approach), Approach to Stop & Stop  Diverging route, where applicable  Turnout speed is shown in timetable Signaling indicates selected route: Signal Systems – Route Signaling 22 September 2010

21. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida21 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida21 Minimum warning time by state regulation or FRA is 20 seconds. Highway Crossing Protection 22 September 2010

22. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida22 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida22 20 seconds – Any Speed Constant Warning - Grade Crossing Predictor Measures train speed and adjusts warning for constant warning time 20 seconds = 2933 feet at 100 MPH 20 seconds = 733 feet at 25 MPH Fixed Track Circuit Approach - Varies with train speed 80 seconds at 25 MPH Highway Crossing Protection 22 September 2010

23. SCORT/TRB Rail Capacity Workshop - Jacksonville Florida23 SCORT/TRB Rail Capacity Workshop - Jacksonville Florida23 Highway traffic signal pre-emption at nearby intersections. When train approaches, highway traffic signals prevent turns towards crossing, while allowing cars to clear crossing. Highway Crossing Protection 22 September 2010